The present invention relates to syringes. In particular, but not exclusively, the invention relates to syringes having means to limit the dose that may be dispensed by the syringe.
Pre-filled syringes of medicine are supplied to hospitals and other medical centres. Syringes are generally available in a number of standard sizes to provide such doses as 1, 3, 5, 10, 20, 30 and 50 ml. An individual patient may require a dose which is not one of these standard volumes. Therefore, a combination of standard doses will be supplied. This adds to the cost of treatment and causes greater discomfort to the patient. Combining standard doses can also cause error in the dosage applied, and lead to a decrease in accuracy of the dosage dispensed.
It is known to provide standard syringes which include a clamping device mounted to the plunger to limit the volume of fluid that is dispensed, thereby allowing non-standard dosages. These clamping devices are selectively positionable along the plunger at discrete locations. However, accidental movement of the clamping device can occur. Also, for disposable syringes, it is advantageous to provide a simple method of permanently locking the clamping device at a specific dosage.